Carburetor



Jan. 17, 1933. F. A. KO'MMER ET AL 1,894,354

CARBURETOR Filed May 7. 1951 2 Sheets-Sheet 1 F650 iIQ OMMA'Z 0 7'70 HE/VN/A/C INVENTOR'5 v w ATTORNEY Jan. 17, 1933. F. A. KOMMER ET AL CARBURETOR Filed. May 7, 1931 2 Sheets-Sheet 2 6.50 4 KaMMeZ NAN/v6 077-0 l l:ENTOR6 ATTORNEY Patented Jan. 17, 1933 UNITED STATES PATENT OFFICE FRED A. KOMMER AND OTTO HENNING, 01 ST. LOUIS, MISSOURI, ASSIGNOBS TO CARTER CARBURETOB CORPORATION, OF ST. LOUIS, MISSOURI, A CORPORATION 01 DELL:-

WARE

OABBURETOB Application filed Kay 7, 1831. Serial No. 535,704.

It will be understood that the invention is susceptible of many modificatlons, and, accordingly, we do not wish to be limited in our protection, except as set forth in the accompanying claims.

This invention relates to carburetors and particularly to devices in carburetors for so controlling the air and fuel mixture as to produce a mixture suitable for start ng under low temperature conditions. The inventlon also relates to devices in carburetors for producing an abnormally rich mixture for warming up purposes and controlling th1s abnormally rich mixture in accordance with the speed of the engine so that, as the speed increases, there will be no danger of serlously flooding the engine with fuel.

In previous carburetors of the plain tube type, the mixture for starting purposes has generally been controlled by a choke or air valve, which valve was closed or partlally closed during starting. After starting and during the warming up period, the choke was partially opened to prevent the supplying of too rich a mixture to the engine. With such devices, it was difficult or impossible for the operator to determine just how much he should open the choke for a given operating condition. The difliculty was increased by the fact that with every change in speed as well as with every change in power demanded, the ideal position for the choke would vary. The operator had no means of readily finding the correct position for the choke valve and could not hope to do more than get some kind of a rough adjustment therefor.

A relief Valve was sometimesincorporated in the choke valve so that when the engine started to run under its power with the choke valve in fully closed position, more air would be drawn through the relief valve into the carburetor, thereby preventing stalling of the engine. This relief valve, however, did not help the warming up condition, for the extension required on the relief valve to produce a proper suction for cold starting was so great that it would never open except when the choke valve proper was in fully closed position. It should be noted that the provision of two relief valves opening at different suctions would not solve the problem, for the warm up relief valve would necessarily open at a lower suction than the starting relief valve, with the result that the starting relief valve would never open at all.

An object of this invention is to produce a generally improved carburetor having an improved and easily regulated device for controlling the fuel mixture during both starting and warming up periods.

Other objects will appear from the following specification and claims:

The invention will be better understood upon reference to the following drawings in which:

Figure 1 is an elevation of a carburetor embodying our invention, parts being shown in section for better illustration thereof.

Figure 2 is a plan view of the air horn of the carburetor.

Figure 3 is a cross sectional view of the air horn taken along the line 3-3 of Figure 2. In Figure 3, the choke valve is shown in partially closed position.

Figure 4 is a sectional elevation of the air horn of the carburetor taken along the line 4- 1 of Figure 3, the choke valve being in fully open position.

Figure 5 is a sectional view taken along so the line 3-3 of Figure 1 with the choke valve in fully closed position.

Figure 6 is a detail view of the warm up valve.

Figure 7 is a detail view of the bracket 25. 35

Figure 8 is a detail view of the latch 28.

The reference numeral 1 indicates the main body of a carburetor having a flange 2 at the lower end thereof for attachment to the intake manifold of an internal combustion engine. The carburetor shown is of the downdraft type, and the air is admitted through the air horn 3, which is provided with a cylindrical portion 4 at its upper end so that an air cleaner may be attached if desired.

The flow of air and fuel mixture through the carburetor is controlled by a conventional throttle valve 5 and also by the choke valve 6.

It will be understood that this refers to the whole choke valve assembly, including the relief valve 7 and warm up valve 8, as well as the solid portion 6 of the choke valve. It will also be understood that some air is admitted throu h the idle tube 9 and admission port 10, ut the amount of air admitted in this manner is comparatively small and chiefly affects the idling operation when the choke valve is in open position.

The fuel is admitted to the carburetor through the fitting 11 from which it passes into the float chamber 12. In the float chamber it is maintained at a substantially constant level A--A by conventional float mechanism not shown. The fuel is discharged into the throat of the venturi 40 in the carburetor by means of the nozzle 13 which communicates with the float bowl by means of the passage. It will be noted that the discharge outlet of the nozzle 13 is just above the fuel level AA so that the fuel will not spill out through the nozzle when the carburetor is not in operation.

The choke valve 6 is mounted on the shaft 15 which is keyed or otherwise fastened to a suitable operating arm 16. A clamp 17 is provided near the end of the operating arm or attachment to a Bowden wire or suitable operating rod. A suitable spring 18 is mounted on a shaft 15 and so connected as to yieldably hold the choke valve in open position. The choke valve proper is of substantially semi-circular formation, as indicated at 6, and is rigidly secured to the choke shaft 15 by means of screw or rivets 19.

The central part of the member 6 is cut out as indicated at 20 to make room for the bearing portion 21 of the warm up valve 8. The warm up valve 8 is provided with an extension 22 adapted to contact with the solid portion 6, as indicated in Figure 3, to limit the bin ing movement of the warm up valve in one irection. A'spring 23 is attached to the warm up valve, as indicated at 24,-and to the solid portion 6 by means of the bracket 25. It Wlll be noted that the bracket 25 is secured to the solid portion 6 by means of a rivet 26 and that a pin 27 passing through the bracket serves as an anchor for the end of the spring 23.

A latch 28 is pivoted on the pin 27 and normally held in the position indicated in Figure 1 by the spring 29. The latch is provided with a projection 30 which is adapted to contact with the upturned end of the projection 22, as indicated in Figure 5. It will be understood that this contact only occurs when the choke is in fully closed position, as shown 651 guide the valve and also to retain the spring in Figure 5. A relief valve 7 is mounted in the member 6, and a plurality of calibrated openings 31 are controlled by the relief valve.

A spring 32 yieldably holds the relief valve in closed position, and it will be understood that a suitable stem 33 may be provided to in proper position. The strength of the spring 32 is calibrated with respect to the area of the openings 31 so as to open under the suction produced by the engine when it .starts to run under its own power with the choke in fully closed position. The exact amount of this motion will vary with diflerent types of carburetors, but, for instance, certam carburetors r uire valves which open under a suction oi to 1% pounds per square inch. 5

The spring 23 is calibrated with respect to the area of the warm up valve 8 in such a manner that when the choke valve and parts are in slightly open position, for instance, as indicated in igure 3, the valve 8 will open or close in accordance with the amount of air being drawn by the engine. The exact operating pressure required to open the valve 8 will vary with different installations, but it may be stated that if the engine is found to get too rich a mixture with a given strength of the spring 23, then a weaker spring should be used, and vice versa.

It will be understood that the strength of thespring 23 vas well as the strength of the spring 32 is carefully calibrated to permit a certain degree of opening for the valve correspondlng with a certaindegree of suction applied. In order to correlate the amount of air admitted by the valves with the requirements of the motor, it is highly desirable that the suction of the engine should be applied direct to the suction operated valves.

If the throttle valve were left in closed 0- sition, serious interference with the suction would result. On the other hand, if the throttle should be fully opened, the engine would be caused to race, which is undersirable when the engine is first started.v We have accordingly pro'videda link 41 connected to the choke valve operating arm 16 and also to a crank 42 which is loosely mounted on the throttle shaft 43. The crank 42 has an arm 44 which is adapted to contact with the point of screw '45 which is carried by the throttle operating arm 46.

With the parts as shown in Figure'l, the

throttle is in fully closed position, and the choke is in fully open position. The throttle may be turned to fully open position (in an anti-clockwise direction with referencg to Figure 1) without any interference with the lever 42. When the choke valve is closed, the operating lever 16 is turned in a clockwise direction, the link 41 moves upwardly, and the projection 44 moves in an anti-clockwise direction, so as to cause the opening of the throttle to a predetermined position. In this manner, the suction of the engine is communicated direct to the valves 7 and 8 without interference by the throttle as lon as the engine is operating at low speeds. owever, the throttle is not in fully open position, and

the engine is accordingly kept from racing during the warm up period.

The operation of the device is as follows:

Upon starting the engine under low temperature conditions, the shaft 15 is rotated by means of the operating arm 16 to the posltion shown in Eigure 5. During this movement, the end ofv the latch 28 contacts with the side of the air horn, as indicated at 33, thereby causing the latch to be rotatedon the pivot 27 in an anti-clockwise dlrectlon, so that the projection 30 will move toward the member 6 and into the path of the upturned portion of the projection 22 on the warm up valve 8. The valve 8 contacts with the inner wall of the air horn before the choke valve 6 has reached the limit of its movement. The member 8 accordingly stops rotating and permits the member 6 to continue in its clockwise rotating movement until it reaches the position shown in Figure 5. The projection 22 then contacts with the projection 30, as indicated, and the opening movement of the warm up valve 8 is positively prevented.

The only air supply to the engine under these conditions is the amount which may enter by leakage or through the port 10'. During cranking speeds, substantially all of the suction in the engine is accordingly concentrated on the nozzle 13, and fuel is drawn from the nozzle in large quantities. As soon as the engine gets suflicient fuel to fire and begins to run of its own accord, the suction immediately increases and the valve 7 opens, thereby permitting a calibrated flow of air through the ports 31. v

The engine may be permitted to operate under these conditions until the operator releases the choke valve. When this is done, the parts assume the position shown in Figure 3.

It should be understood that no exact positioning of the parts is necessary, but, if desired, the strength of the spring 29 may be increased to such a point that the operator will be able to detect the contacting of the latch 28 with the side of the air horn. In this way, the operator may locate the choke Valve very accurately. With this construction, however, we have found that that is not always necessary, for satisfactory operation may be obtained with considerably different positions of the choke valve.

With the parts in this position, the engine is operated as long as may be necessary for a suitable warm up. With varying speeds and loads on the engine, the valve 8 will automatically vary its position so that a proper mixture will at all times be supplied.

After the engine is sufiiciently warmed up, the choke valve is operate'd to fully open position, as shown in Figure 1, and the carburetor then continues to operate as a plain tube carburetor, that is, without any variation of the Size of the air inlet in accordance with the speed or load of the engine.

We claim:

1. In a carburetor, means forming an air inlet passageway, a transverse shaft mounted in the walls of said passageway, a semi-circular choke valve rigidly attached to said shaft, a semi-circular Warm u valve pivotally mounted on said shaft, spring means for normally holding said warm up valve in line with said choke valve, a latch carried by said choke valve, said latch being adapted to contact with the walls of said air passage when the choke is in closed position, said latch being constructed and arranged to prevent the opening by suction of said warm up valve when the'choke valve is in fully closed position.

2. In a carburetor, walls forming an air illlet passageway, a choke shaft transversely mounted in said walls, a solid valve portion carried by said choke shaft, a suction operated valve also carried by said choke shaft, a by-pass port in one of said valves, and a spring pressed valve for controlling said bypass port.

3. In a carburetor, walls forming an air inlet passageway, means for substantially closing said passageway against the admission of air, suction operated means operable by comparatively high suction to admit small quantities of air to said carburetor when said passageway is closed, and suction operated means for admitting larger quantities of air to said carburetor, said last named suction operated means operating at a comparatively low suction, and means for preventing the operation of said last named suction operating means when said passageway is fully closed.

4. In a plain tube carburetor, means forming a mixing conduit having a venturi therein, a nozzle discharging into said venturi, means for supplying fuel to said nozzle, a choke valve controlling the admission of air to said mixing conduit, a valve for admitting air to said mixing conduit by starting suction when said choke Valve is in closed position, a warm up valve for varying the admission of air to said mixing conduit when said choke valve is in partially closed position, and means for preventing the opening of said Warm up valve when said choke valve is in fully closed position.

5. In a carburetor, means forming a mixing conduit, a choke valve mounted near the inlet of said mixing conduit to control the admission of air thereto, a starting valve operated by suction to admit small quantities of air when said choke valve is in fully closed position, a warm up valve operable by a lower degree of suction than said starting valve to admit larger quantities of air when said choke valve is in partially closed position, said starting valve opening only when said choke is in fully closed position, and said warm up valve being constructed and arranged to open only when said choke is in part] open position.

6. n a carburetor, means forming a mixing conduit, a choke valve for controlling the admission of air thereto, a warm up valve carried by said choke valve, a spring for normally holding said warm up valve in one position with respect to said choke valve, said warm up valve being operable by suction when said choke valve is in partly closed position, and a latch carried by said choke valve, said latch contacting with said warm up valve to prevent opening thereof when said choke valve is in fully closed position.

7. In a plain tube carburetor, means forming a mixing conduit, an air inlet passageway for admittin air to said mixing conduit, a fuel nozzle discharging into said mixing conduit, a throttle valve controlling the discharge of fuel mixture from said conduit, a choke valve controlling the flow of air through said air inlet passageway, suction operated starting and warm up valves for admitting air to said mixing conduit when said choke valve is not in fully open position, and a connection between said choke valve and said throttle valve for opening said throttle valve when said choke valve is in closed position, whereby the suction of the engine may be communicated directly to said suction operated valve when said choke valve is in closed position.

8. In a plain tube carburetor, means forming a mixing conduit, a throttle valve near the outlet end of said conduit for controlling the discharge of fuel mixture-therefrom, a choke valve near the inlet end of said conduit for controlling the admission of air thereto, a fuel nozzle discharging into said mixing conduit at a point between said valves, a .pair of suction operated valves operated at difierent suctions to admit air to that part of the mixing conduit between said valves when said choke valve is not in fully open position, means for preventing the opening of one of said valves when said choke valve is in fully closed position, and a connection between said choke valve and said throttle valve for opening said throttle valve when said choke valve is closed, whereby suction applied at the discharge end of the mixing conduit will be communicated directly to said suction operated valves.

9. In a carburetor for internal combustion engines, means forming a mixing conduit having an air inlet and a mixture outlet, a

suction operable valve in said air inlet, saidvalve being constructed and arranged to be operated by comparatively low suction, a second suction operating valve constructed and arranged to be operated by comparatively high suction, a locking device for preventing the operation of said first named valve,

means for releasing said lock after the motor has started to run under it own power to permit the valve to open by suction,- and means for moving said valve to open position regardless of suction.

10. In a carburetor for internal combustion engines, means forming a mixing conduit, suction operated valve means for admitting air to said mixing conduit, said valve means comprising a part operable b comparatively low suction and a part opera le by comparatively high suction, a latching device for preventlng the operation of said first named part, means for engaging said latching device with said part to hold it in closed position when the engine is to be started cold, and means for releasing said latch after the engine has started to run under its own power.

11. In a carburetor for internal combustion engines, means forming a mixing conduit, a suction operated fuel nozzle in said mixing conduit, a throttle valve in said mixing conduit posterior to said nozzle, suction operable valve means for controlling the admission-of air to said mixing conduit, said valve means comprising a shaft, a valve eccentrically mounted on said shaft, whereby it will be operated by suction, yieldable means for holding said valve in closed position when the engine is to be started cold, said yieldable means being comparatively easily displaceable so that said valve may be opened by comparatively low suction, a second valve for admitting air to said mixing conduit when said first named valve is closed, yieldable means for holding said valve in closed position, said last named yieldable means having comparatively greater strength with respect to the area of its valve than said first named yieldable means, latch means for reventing the operation by suction of said rst named valve, means for releasing said latch, and means for moving at least one of said valves to full open position regardless of suction.

12. In a plain tube carburetor for internal combustion engines, means forming a mixing conduit, a throttle valve in said conduit, a suction operated nozzle anterior to said throttlevalve, means operable to control the admission of air to said mixing conduit comprising a suction operable valve of comparatively large area, said valve being operable by comparatively low suction, a suction oper-' ated valve of smaller area, said last named valve being operable only by a comparatively high suction, means for opening or closing said larger valve regardless of suction, and means for preventing the opening by suction of said larger valve.

13. In a carburetor for internal combustion engines, means forming a mixing conduit having an air inlet and a mixture outlet, a throttle valve controlling said outlet, choking means for controlling said inlet, said choking means comprising a part of comparatively large area operable by comparatively low suction and a second part of comparatively small area operable only by comparatively high suction, means for closing said choking device when the engine is to be started cold, and means for automatically opening said throttle during the starting operation. Y

14. In a carburetor for internal combustion engines, means forming a mixing conduit having an air inlet and a mixture outlet, a throttle valve controlling said outlet, choking meansfor controlling said inlet, said choking means comprising a part of comparatively large area operable by comparatively low suction and a second part of comparatively small area operable only by comparatively high suction, means for closing said choking device when the engine is to be started cold, means for automatically opening said throttle during the starting operation, means for latching said larger part of the choke device in closed position, and means for releasing said latch after the engine has begun to run under its own power.

15. In a down draft carburetor, means forming a substantially vertical mixing conduit, a throttle at the lower end of said con-' duit, a venturi in said conduit above said throttle, a suction operated fuel nozzle discharging into said conduit at a point above said throttle, a choke valve assembly mounted in said mixing conduit above said nozzle, said assembly comprising a transverse shaft, a comparatively large valve portion and a comparatively small valve portion carried b said shaft, said large portion being operable by comparatively low suction, and said small portion being operable by said high suction, said valve portions being mounted substantially in the same plane,.whereby upon rotation of said shaft they may either be placed in a position of minimum resistance to the flow of air, or moved to a position in which the flow of air will be substantially cut oil, latch means for preventing the operation of said larger valve portion by suction, and means for releasing said latch.

16. In a down draft carburetor, means forming a substantially vertical mixing conduit, a throttle at the lower end of said conduit, a venturi in said conduit above said throttle, a suction operated fuel nozzle discharging into said conduit at a point above said throttle, bafile means surrounding the outlet of said nozzle to catch fuel discharged therefrom and cause it to drip down directly on said throttle, baffle means causing fuel from nozzle to fall on central ortion' of ed in said mixing conduit above said nozzle, said assembly comprising a transverse shaft, a comparatively large valve portion and a comparatively small valve portion carried by said shaft, said large portion being operable by comparatively low suction, and said small portion being operable by saidhigh suction, said valve portions being mounted substantially in the same plane, whereby upon rotation of said shaft they may either be placed in a osition of minimum resistance to the flow 0 air, or moved to a position in which the flow of air will be substantially cut oif, latch means for preventing the operation of said larger valve portion by suction, and means for releasing said' latch.

17. In a down draft carburetor for internal combustion engines, means forming a substantially vertical mixing conduit, a throttle valve at the lower end of said conduit, choke valve means at the upper end of said conduit, a main venturi in said conduit between said valves and nozzle, a suction operated fuel nozzle discharging into said conduit between said valves and above the throat of said main venturi, a primary venturi surrounding the discharge outlet of said nozzle, the lower end of said primary venturi terminating adjacent the throat of the main venturi and being adapted to drip the fuel squirted from said nozzle directly down on to saidthrottle when it is in partially closed position, said choke valve means comprising a comparatively large portion operable by a comparatively low suction, a comparatively small portion operable by comparatively high suction, and means independent of suction for opening and closing said choke valve means.

18. In a down draft carburetor for internal combustion engines, means forming a substantially vertical mixin conduit, a throttle valve at the lower end 0 said conduit, choke valve means at the upper end of said conduit, a main venturi in said conduit between said valves and nozzle, a suction operated fuel nozzle discharging into said conduit between said valves and above the throat of said main venturi, a primary venturi surrounding the discharge outlet of said nozzle, the lower end of said primary venturi terminating adjacent the throat of the main venturi and being adapted to drip the fuel squirted from said nozzle directly down on to said throttle when it .is in partially closed position, said FRED A. KOMMER. OTTO HENNING.

.our hands. throttle valve, a choke valve assem ly mount- 

